The Animal Physiology Core will play an essential role in many studies in each of the projects. Procedures supported by this core include cannulation of brain ventricles and specific hypothalamic nuclei of rats and mice, jugular vein catheterization for blood sampling, collection of brain and other tissues at that time of study termination and preparation of those materials for storage or for further analysis, metabolic studies including oxygen consumption and respiratory quotient by calorimetry, physical activity measurements, meal pattern analysis, and body composition analysis by magnetic resonance spectroscopy. Finally, this core will support the performance of specific biochemical or molecular assays that are common to each project including real time PCR ofhypothalamic rnRNA species in rats and mice and western blot analysis for detection of specific signaling molecules (e.g., phospho-ACC and phospho-PKB). Animal Physiology Core personnel already have the expertise and access to resources necessary to perform all of the experiments included in this proposal, and existing protocols will ensure that the goals of this core are efficiently met.